1. Field of the Invention
This invention relates generally to phase/frequency detectors, and, more specifically, to phase/frequency detectors suitable for applications involving signal with small modulation indices.
2. Related Art
Many wireless applications, such as Bluetooth, Home RF and WLAN, require low complexity phase/frequency detectors which are capable of detecting GMSK/GFSK signals have small modulation indices, i.e., modulation indices less than about 0.4. Detectors based on analog limiters and discriminators have been widely in some wireless applications, but they typically imply large die sizes and off-chip components. Correlator type digital detectors have been used in some wireless applications, but these detectors are typically not sensitive enough to detect signals having small modulation indices. Sigma delta frequency converters have been used in wireline FM applications, but entail high complexity and lack of compatibility with wireless applications.